Excavation devices for digging holes and trenches to uncover buried objects such as pipelines and the like are well known in the art. When using a mechanical excavation device, such as a front-end loader or back hoe, to uncover a buried pipeline, strict guidelines are imposed to ensure that the devices do not get too close to the pipeline. These guidelines are imposed for safety reasons and particularly to guard against accidental rupture of the pipeline. This is particularly important when the pipeline carries flammable liquids, gases or other explosive substances.
In typical operating conditions, the above-mentioned machines are used to excavate the area adjacent the pipeline and once this is done, the remaining earth over the pipeline is excavated by shovel or other suitable hand carried tool. Although this method of excavating a buried object works satisfactory, labour costs and the time taken to uncover the pipeline are significant. In addition, if the pipeline is buried fairly deep in the earth, the walls of the excavation must be shored while workers are digging. This necessary safety precaution further increases costs and the time taken to excavate the pipeline.
To overcome these problems associated with the above-described prior art method of excavating a pipeline, a hydro-vacuum excavating system has been developed. This prior art system includes two separate devices each of which is carried by a large transport truck. One of the devices is in the form of a high pressure water sprayer which includes a large tank, holding water to be sprayed, supported on the chassis of the truck. A boom is on the top of the tank and supports a hose extending from the tank. The boom is movable to allow the discharge end of the hose to be directed to an excavation site. A high pressure pump forces water from the tank through the hose. The water exits a nozzle at the discharge end of the hose in a narrow stream at a sufficient pressure to cut a swatch through the ground at the excavation site. Depending on the setting of the nozzle, the size of the swatch cut by the narrow stream can be varied.
The other device is in the form of a cleaner and similarly includes a tank supported by the chassis of the other truck. The tank is designed to receive the earth dislodged the stream of water together with the sprayed water. A hose extends from the tank and is supported by a movable boom to allow the intake end of the hose to be directed to the excavation site. The cleaner includes a blower to create the necessary suction in the hose to draw the water and dislodged earth into the tank.
Although this system works satisfactorily, it is not suitable in many environments. For example, in isolated areas the roadways often are unsuitable for passage of the large trucks carrying the system. Also, in many areas the ground on which work is to be performed is not capable of supporting the large trucks carrying the system. Accordingly, there exists the need for an excavation apparatus which is suitable in practically all environments and which is readily transportable.
It is therefore an object of the present invention to provide a novel excavation apparatus.